Field of the Invention
The present invention relates to an organic light emitting display device and a method of manufacturing the same.
Discussion of the Related Art
As a type of new flat panel display device, organic light emitting display devices are self-emitting display devices, and have a better viewing angle and contrast ratio than liquid crystal display (LCD) devices. Also, since the organic light emitting display devices do not need a separate backlight, it is possible to lighten and thin the organic light emitting display devices, and the organic light emitting display devices have excellent power consumption compared to LCD devices and the other flat panel display devices. Furthermore, the organic light emitting display devices are driven with a low direct current (DC) voltage, have a fast response time, and are low in manufacturing cost.
In organic light emitting display devices, an electron and a hole are respectively injected from a cathode and an anode into an emitting material layer, and, when an exciton in which the injected electron and hole are combined is shifted from an excited state to a base state, light is emitted. In this case, the types of organic light emitting display devices are categorized into a top emission type, a bottom emission type, and a dual emission type according to an emission direction of light, and categorized into a passive matrix type and an active matrix type according to a driving type.
Therefore, in an organic light emitting display device, when a scan signal, data signals, and power are supplied to a plurality of sub-pixels which are arranged in a matrix type, a selected sub-pixel emits light to display an image. In this case, each of the plurality of sub-pixels includes: a thin film transistor (TFT) which includes a switching TFT, a driving TFT, and a capacitor; and an organic light emitting element which includes a first electrode connected to the driving TFT included in the TFT, an organic layer, and a second electrode.
Recently, a display device of a high-resolution product group is desired. In order to implement the high-resolution display device, it is required to increase the number of pixels per unit area, and high luminance is needed. However, due to a limitation in the structure of the organic light emitting display device, efficiency characteristic is limited, and a current increases. For this reason, an electrical and thermal stress to the device increases, causing a reduction in the reliability of the device.
Therefore, in order to implement a high-resolution product, research is being done for a method of overcoming a structural limitation in the organic light emitting display device and a method of addressing problems such as an increase in power consumption, a reduction in a service life, and a degradation in reliability.